05474865 is referenced by 143 patents and cites 7 patents.

A globally planarized binary optical mask has absorbers embedded (buried) in the mask substrate, instead of on the surface of the mask. Light scattering at rough vertical edges of absorbers of prior art masks are reduced or eliminated. Also, due to the buried nature of the absorbers, a triple singularity point encountered in prior art masks at the interface of three environments of quartz, absorber and air, no longer exists. The buried absorbers have an offset distance from the surface of the substrate so that with a minimum effective offset distance, defects and contaminants at the surface of the mask are no longer in the image plane, wherein alleviating a need for a pellicle to protect the mask surface. By reducing light scattering and distortion, the mask of the present invention allows for conventional optical lithography to be extended to ranges of shorter wavelength.

Title
Globally planarized binary optical mask using buried absorbers
Application Number
8/342940
Publication Number
5474865
Application Date
November 21, 1994
Publication Date
December 12, 1995
Inventor
Prahalad K Vasudev
Austin
TX, US
Agent
William W Kidd
Assignee
Sematech
TX, US
IPC
G03F 9/00
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